Angelina Jolie has always been outspoken about issues that matter to her, and now, for the first time, she's revealing a very personal one: her decision to undergo a preventive double mastectomy after discovering she carries the BRCA1 gene, which increases the risk of developing breast and ovarian cancer.

"My doctors estimated that I had an 87 percent risk of breast cancer and a 50 percent risk of ovarian cancer, although the risk is different in each woman," she writes today in a New York Times op-ed. "Once I knew that this was my reality, I decided to be proactive and to minimize the risk as much as I could."

Jolie, 37, lost her mother in 2007 to ovarian cancer, and she explains in the article that her six children with partner Brad Pitt contributed to her decision to have the surgery--and now, she's speaking out about it to educate other women in her situation about their options.

"Cancer is still a word that strikes fear into people's hearts, producing a deep sense of powerlessness. But today it is possible to find out through a blood test whether you are highly susceptible to breast and ovarian cancer, and then take action," she writes. "The decision to have a mastectomy was not easy. But it is one I am very happy that I made. My chances of developing breast cancer have dropped from 87 percent to under 5 percent. I can tell my children that they don't need to fear they will lose me to breast cancer."

She continues that her own process, which included three procedures, began on Feb. 2 and concluded April 27. Ultimately, the Oscar winner, who said that the process made her "feel empowered" and "in no way diminishes my femininity," had a breast reconstruction with implants and calls the results "beautiful."

"It is reassuring that [my children] see nothing that makes them uncomfortable. They can see my small scars and that's it," she explains. "Everything else is just Mommy, the same as she always was. And they know that I love them and will do anything to be with them as long as I can."

She also credits her partner of several years, Pitt, for standing by her through the ordeal.

"I am fortunate to have a partner, Brad Pitt, who is so loving and supportive," she writes. "So to anyone who has a wife or girlfriend going through this, know that you are a very important part of the transition. Brad was at the Pink Lotus Breast Center, where I was treated, for every minute of the surgeries. We managed to find moments to laugh together. We knew this was the right thing to do for our family and that it would bring us closer. And it has."

Jolie adds that the specifics of her regimen will be posted on the Pink Lotus Breast Center's website, but encourages women with her medical history to get tested and know their options.

"Life comes with many challenges," she writes. "The ones that should not scare us are the ones we can take on and take control of."